The invention relates to the production of bulky, continuous filament yarns.
United Kingdom Patent Specification No. 732,929 describes and claims a bulky, continuous filament yarn and a method and apparatus for its manufacture in which a multi-filament flat yarn is subjected to the action of a fluid stream in a zone of sufficient turbulence to separate the individual filaments and to form them into ring-like, crunodal loops and other convolutions. To accommodate the formation of these loops and other convolutions, the yarn is fed into the turbulent zone at a greater speed than it is withdrawn.
Whilst the resultant bulky yarn is suitable for the production of fabrics for some end uses, it does not have sufficient bulk for fabrics of some other end uses. For example: boucle type yarns suitable for the production of upholstery fabrics cannot be produced by subjecting a single end of yarn to turbulence. In practice, fabrics produced by subjecting a single yarn end to turbulence are subject to pluckiness and lack of stability.
It has therefore been proposed, in United Kingdom Patent Specification No. 893,020, to produce core and effect yarns in which a yarn providing the core filaments of the core and effect yarn are fed into a zone of fluid turbulence at a much lower speed than each of the filaments providing the loops and other convolutions necessary in highly bulked fancy yarn. However, although these core and effect yarns are suitable for the production of upholstery fabrics, they are not suitable for knitted or woven apparel fabrics.